Laboratory tests are an integral part in the diagnosis of diseases in the pediatric age group and are commonly an essential part of the diagnostic workup, which is important for selecting the most appropriate treatment. Many new techniques and laboratory studies have been introduced in the last few years and many have replaced older methods that have become obsolete. It has become essential to the practice of modern pediatrics to be familiar with advances in laboratory medicine and it has become important to meet the demands of the practicing physician. As before, the complexity and sophistication of many tests exceed the capabilities of many office or small hospital facilities. However, when necessary, these tests can be referred to specialized reference laboratories. As in the previous edition, the text of this revised second edition is divided into categories of disease with a brief outline of signs and symptoms that remain integral and essential for diagnosis. This is followed by diagnostic tests, including the most important methods for diagnosis with updates in molecular procedures, DNA, probes, monoclonal antibodies, polymerase chain reaction, immunocytochemical and cytochemical staining, flow cytometry, and cytogenetics. Additional tables and algorithms have been included to add simplification, clarify and to expedite the understanding and selection of diagnostic tests. Clinical Use of Pediatric Diagnostic Tests aims to become essential for the needs of pediatricians, family practitioners, students, residents, pathologists, nurses, practitioners and laboratory technicians.